Using fire to boil water has long been the preferred method for making steam. But now, thanks to specially coated nanoparticles of sand, we can use sunlight.

Researchers at Rice University in Texas made fine grains of sand, much smaller than the width of a human hair, and coated them in gold or carbon. They sprinkled these nanoparticles into water, and then focused sunlight on them. Each particle acted as a nano-sized boiler, absorbing the heat from the sunlight and turning surrounding water molecules from liquid to vapor. This solar steam was produced without having to boil the whole pot, in as quickly as five seconds.

The nano-sized boilers turn sunlight into steam with 80 percent efficiency and could prove a boon in places that lack fossil fuels or electricity. The nanoparticles are easy to make, relatively cheap and can be used over and over again.

The technology could enable folks in resource poor areas to do everything from purifying water to sterilizing surgical equipment. And that might be enough to start a new, if smaller, Steam Age.